Equilibrium and nonequilibrium modeling of hypersonic inviscid flows

Hypersonic flows about ellipses at high angles of attack are analyzed by means of nonequilibrium, equilibrium and inert gas models. It is shown that the technique proposed for the nonequilibrium model, based on a streamline integration of the chemical rate equations, provides accurate results and allows precise computation of the stagnation point conditions, where equilibrium must be attained. Compared with the nonequilibrium one, the equilibrium model underpredicts the bow shock stand-off distance and overpredicts the wall temperature, whereas the inert gas model can only be used as a crude approximation for evaluating the wall pressure.